TCP Server Creation in Python

Introduction

• Focus on creating a TCP server in Python.
• Future video will cover creating a client and demonstrating communication between the server and client.
• Using Windows with Visual Studio Code and Microsoft Python extension.

Understanding Sockets

• What is a Socket?
  • Technical Definition: An internal endpoint for sending and receiving data.
  • Simple Analogy: Like an outlet that provides a power connection, but for data transmission.
• Importance of sockets in penetration testing and data communication.

Socket Module in Python

• Part of the Python standard library.
• To use the socket module, you need to import it in your script.
• Syntax to create a socket:

  socket.socket()
  

Socket Parameters

• Socket Family: Generally specified using socket.AF_INET (for IPv4) or socket.AF_INET6 (for IPv6).
• Socket Type:
  • socket.SOCK_STREAM for TCP (connection-oriented).
  • socket.SOCK_DGRAM for UDP (connectionless).

Important Socket Methods

• bind(): Binds the host and port to a socket.
• listen(): Starts the TCP listener.
• accept(): Accepts incoming TCP connection requests.
• send(): Sends a message over TCP.
• recv(): Receives messages over TCP.
• close(): Closes the socket connection.

Creating a TCP Server

1. Set up Environment

   • Save file as server.py in Visual Studio Code.
   • Make sure to run on Python 3.

2. Import the Socket Module

   import socket
   

3. Create a Socket Object

   server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
   

4. Get Hostname and Bind

   • Get local hostname:

     host = socket.gethostname()
     

   • Specify port (e.g., 444)
   • Bind socket to host and port:

     server_socket.bind((host, port))
     

5. Listen for Connections

   server_socket.listen(3)  # maximum 3 connections
   

6. Accept Connections in a Loop

   while True:
       client_socket, address = server_socket.accept()
       print(f'Connection received from {address}')
       ```
   
   

7. Send Message to Client

   • Create a message:

     message = 'Thank you for connecting to the server!'
     

   • Send message:

     client_socket.send(message.encode())
     

8. Close Client Socket

   client_socket.close()
   

Summary

• Set up a TCP server using the socket module in Python.
• Create socket with specified family and type (TCP).
• Bind to host and port, listen for connections, and handle communication.
• Code will be available on GitHub for further review and testing.

Additional Notes

• Mistakes may occur; clarification and support can be requested in comments or privately via a website.
• Expect improvements and documentation to be added on GitHub.